The primary objective is to determine the effect of the closure of the San Diego County Methadone Maintenance Program on a followup sample of clients enrolled on September 30, 1978, and involuntarily terminated because of the closure. An interview schedule has been designed to collect retrospective longitudinal data on drug use, criminal behavior, employment, and other variables for extended periods prior and subsequent to clinic closure. These results will be contrasted with those from a comparison sample selected from surrounding counties' programs which have continued to the present. A secondary objective is to compare the effectiveness of private (fee-for-service) methadone programs relative to the San Diego County Program (approximately one-half of the followup sample transferred to or subsequently enrolled in a private program within three months of closure of the county facilities). Other objectives include uni- and multivariate analyses of variables related to success in treatment.